1. Field of the Invention
The present invention relates to a mixing/charging port for medical treatment, which is placed on a medical instrument to make it easy and reliable to mix/charge solutions from the outside of a feeding passage or, on the other hand, to collect solutions from the inside of the feeding passage.
2. Description of the Prior Art
In infusing a drug solution or transfusing blood into a patient, it is often necessary to provide a main feeding passage with a side-infusing line in order to mix/charge different kinds of drug solutions or to collect the liquid flowing in the feeding passage as a sample. Conventionally, in this case, a feeding passage of an infusion set provided with a rubber mixing/charging port (cock) for piercing by needles is used and solutions are mixed/charged by piercing the mixing/charging port with an injection needle, etc.
However, in such a method, when piercing the site other than the predetermined piercing site of the mixing/charging port with the needle, the liquid may leak from the site. Another problem is that the injection needle may be contaminated due to a working error, etc. In order to fix and hold a luer, etc. to be inserted (“an insertion member” will be referred to hereinafter), recently, the mixing/charging port capable of holding an insertion member has been considered. An example includes a mixing/charging port equipped with a valve that opens when a male luer located at the tip of a syringe is inserted into the mixing/charging port to push the valve and which closes by itself when the luer is pulled out from the mixing/charging port.
However, in such a mixing/charging port, it is necessary to hold a luer at the mixing/charging port regardless of the state in which the valve is inserted (i.e., valve opens) or the state in which the valve is pulled out (i.e., valve closes). Therefore, there are the following various problems. More specifically, first, it is necessary to deepen a luer receiving part of the mixing/charging port. With such a shape, it is difficult to remove the liquid leaking from the valve, which easily may become unsanitary. Furthermore, in the mixing/charging port having such a deep luer receiving part, the liquid may begin to be mixed/charged in a state in which the luer is not sufficiently inserted into the valve. In this case, if the amount of drug solution to be mixed/charged is small, the administration of an effective amount of drug solution may not be carried out. Secondly, the structure of the valve becomes complicated, which may lead to increasing cost. Furthermore, as the structure of the valve is more complicated, failures are more likely to occur, and the valve is more likely to be broken.
On the other hand, in the conventional simple-structured mixing/charging port (for example, a mixing/charging port merely equipped with a disk-like valve made of an elastic member having a slit), it was difficult to insert a luer of a syringe into the mixing/charging port. If possible, it was difficult to hold the syringe reliably at the mixing/charging port. This is because the conventional disk-like valve is formed of a material having a large elasticity and has a simple structure in which the thick main body is merely provided with a slit, so that the valve exhibits a large resistance when the luer is inserted into the valve, and the valve is deformed largely when the valve holds the luer. However, if the thickness of the elastic member is reduced or a material having a small elasticity is used in order to reduce the resistance when the luer is inserted, the backflow prevention effect of the valve is lowered, which may cause liquid leaking.
In order to solve the above-mentioned problems, there has been a proposal of a mixing/charging port for medical treatment having a simple structure and capable of reliably holding an insertion member, which includes a disk-like valve having an insertion hole at the center, a seating for supporting the lower part of the periphery of the valve with the center of the rear surface side of the valve left unsupported, a cover for restraining the valve by covering at least the upper part of the periphery of the valve with the center on the front surface side of the valve left uncovered, and an anchor means for anchoring the insertion member to the mixing/charging port by inserting the insertion member into the insertion hole and by using the edge portion of the cover provided with a fitting hole.
FIGS. 1A, 1B and 1C are projection drawings from three directions of an example of a conventional mixing/charging port for medical treatment. That is, FIG. 1A is a longitudinal sectional view of a mixing/charging port; FIG. 1B is a cross sectional view of the mixing/charging port along line I-I in FIG. 1A; and FIG. 1C is a plan view of the mixing/charging port, respectively.
In FIG. 1, reference numeral 1 denotes a disk-like valve, 2 denotes a cover, and 3 denotes an insertion hole. Furthermore, reference numeral 4 denotes an insertion member, 5 denotes an annular rib, 6 denotes a fitting hole, 7 denotes a seating, 8 denotes a passage, and 9 denotes a hook. In this structure, the valve 1 is sandwiched between the hook 9 of the cover 2 and the annular rib 5.
However, in the above-mentioned mixing/charging port for medical treatment, there has been a problem in that when absorbing air bubbles generated inside the mixing/charging port from the insertion hole 3, air bubbles that enter between the depressed part of the valve 1 and the inner part of the mixing/charging port cannot be absorbed efficiently. Consequently, because of the presence of air bubbles that have not been able to be absorbed, there remains a possibility that an air bubble may be a contaminant when transfusing blood or infusing a liquid medicine into a patient, which may lead to a problem in that medical treatment cannot be carried out safely.
For example, when an insertion member 4 is inserted into a conventional mixing/charging port for medical treatment, the valve 1 is depressed and the insertion member 4 is held by the elastic force of the depressed part of the valve 1 and the fitting hole 6 as shown in the sectional view of FIG. 2. However, between the tip portion of the depressed part of the valve 1 and the seating 7, a certain region A is created. If air bubbles enter this region A, the air bubbles cannot be absorbed from an absorption port of the insertion member 4.